Originally Posted by
buddiiee
Like Merziac here said, the way Masi's frame builders measured frames may be different than the common way here; possibly being 2cm's smaller than the perceived size. Are you guys aware of their builders measuring their frames differently? Maybe all those 52's out there are really 50s?
buddiiiee, you are correct, Masi measured his frames differently than center to center. He measured them center to top. Well where is "top". Here are pictures of my Italian Masi frame I got directly from the velodrome in 1972. It is marked on the down tube socket of the BB shell as a 58. Actually it is marked V58. I've heard that the letter in front of the numbers (in my case a V) is the indication which city (or subcontractor) built the frame. I put my Masi on one of my fixtures I have laser cut out of stainless steel in Ukraine. That way I can read directly off the fixture almost every dimension. It is also what I use to design my frames too. According to my fixture, my 58 cm frame measures 55.8+. In other words not quite 559 mm.
It also does not have a perfectly level top tube. Another one of my pictures shows it is not level according to my fixture level. If I remember right it slops up 6mm. The seat tube angle is 72 1/2º and the head tube angle is 73º with 50 mm of rake on my twin plate fork. My fixture also lets me read the straddle height of a top tube (after I set the tire diameter). It reads 83cm. If anyone is curious about other dimensions I can provide those.
My V58 1972 Italian Masi on my design fixture
The seat tube length reads just a hair over 558mm
A pic of its size markings
A pic that shows the top tube is not level using my fixture accessory I use to level my TT piece